Mineral Wool Waste Research Articles

Nanostructural evolution of alkali-activated mineral wools

Mineral wools are the most widely used building insulation material worldwide. Annually, 2.5 million tonnes of mineral wool waste are generated in the EU alone, and this is a largely unutilised material that is landfilled or incinerated. However, mineral wool wastes are promising precursors for production of alkali-activated cementitious binders due to their favourable chemical and mineralogical composition and high surface area. Alkali-activation is therefore a valuable route for valorisation of large quantities of mineral wool waste. This study resolves the phase assemblage and nanostructure of reaction products formed upon alkali activation of stone wool and glass wool by sodium hydroxide and sodium silicate solutions with X-ray diffraction, electron microscopy and solid state nuclear magnetic resonance spectroscopy experiments probing 27Al and 29Si. The stone wool-based alkali-activated binder comprises an amorphous sodium- and aluminium-substituted calcium silicate hydrate (C-(N-)A-S-H) gel, an amorphous sodium aluminosilicate hydrate (N-A-S-H) gel and small amounts of the layered double hydroxide phase quintinite and zeolite F. The glass wool-based alkali-activated binder comprises an amorphous Ca- and Al-substituted sodium silicate (N-(C-)(A-)S–H) gel. Gel chemical composition and reaction kinetics of alkali-activated mineral wools are shown to be dependent on the activating solution chemistry, with reaction rate and extent promoted by inclusion of a source of soluble Si in the reaction mixture. This work provides the most advanced description of the chemistry and structure of alkali-activated mineral wools to date, yielding new insight that is essential in developing valorisation pathways for mineral wools by alkali activation and providing significant impetus for development of sustainable construction materials.

Development and energy evaluation of novel integrated envelopes without thermal bridges

In this study, to eliminate thermal bridges caused by traditional insulation system, a new synthesis method of novel integrated envelopes was proposed. This proposed integrated envelope consisted of two layers, including the base part and insulation part. Construction solid wastes were applied as raw materials and the influences of the raw material ratio, additive content, and sintering temperature on micro and macro performances were investigated. The experiment results show that the optimal sample was sintered at 1200 °C, with raw materials of 50 wt% waste glass, 40 wt% mineral wool waste, 10 wt% waste quartz for both parts, and with another 2 wt% SiC and 1–3 wt% Na3PO4·12H2O for the insulation part. The corresponding optimal samples have the best performance, such as the dense base, a uniform pore structure, and good thermal insulation. Moreover, the energy analysis results revealed that this proposed material has good environmental sustainability and could efficiently reduce the negative impact of thermal bridges with the energy conservation of 8.18%.

Mineral wool waste-based geopolymers

Mineral wools –a general term for stone wool and glass wool– are the most common building insulation materials in the world. The annual amount of mineral wool waste generated in Europe totaled 2.3 Mt in 2010 – including wastes from the mineral wool production and from the construction and demolition industry. Unfortunately, mineral wools are often considered unrecyclable due to their fibrous nature and low density. Thus, the utilisation of post-consumer mineral wool waste in different applications remains low.Mineral wools have a great potential as geopolymer precursors as they have suitable chemical and mineralogical compositions. As geopolymers can provide significant CO2 emission reductions compared to traditional Portland cement concretes, using mineral wool waste as geopolymer precursor would be an attractive utilisation path. Here, we show that mineral wool waste can be geopolymerised to form sustainable cements with good mechanical properties. Geopolymerisation of mineral wool waste therefore offers an attractive route for waste valorisation and production of low-CO2 cements.

Development of lightweight composites based on foam glass aggregate

Building composites based on various types of lightweight aggregate have been widely used in the last decades for production of precast elements (e.g. panels) or whole structures with a good thermal insulation/mechanical properties ratio. The presented research investigated the feasibility of using foam glass aggregate, prepared from waste glass powder, in lightweight insulating composites for building industry. The effect of various binders (both organic and inorganic), binder/filler ratios and 3 types of fibres addition (PET, cellulose and mineral wool waste) on the physico-mechanical properties (bulk density, compressive strength) and thermal conductivity of the composite was evaluated. The results indicate, that applicable composites with sufficient mechanical parameters and low thermal conductivity (coefficient of thermal conductivity about 0,09 W/(m·K) can be prepared using both types of binders.

Utilization of mineral wool waste and waste glass for synthesis of foam glass at low temperature

Abstract To reduce the energy consumed by building part, a new method of producing foam glass at low temperature was proposed in this study. Mineral wool waste and waste glass recycled from building construction and demolition (C&D) process were used as major raw materials. In the meanwhile, calcium carbonate (CaCO3), borax (Na2B4O7·10H2O) and sodium phosphate (Na3PO4·12H2O) were added as extra additives, which played the part of foamer, fluxing agent and foam stabilizer, respectively. The effects of different content of each additives and different sintering temperature on the properties of foam glass were investigated. Bulk density, cross-section view and microstructure of the specimens were showed. The experiment results showed that the optimal content of raw materials and additives was 40 wt% mineral wool waste, 60 wt% waste glass, 20 wt% borax, 1–2 wt% calcium carbonate and 2 wt% sodium phosphate, and its optimal sintering temperature was 800 °C. The specimen sintered at this optimal condition had the most uniform foam structure and low bulk density of 0.7 g/cm3. Finally, EnergyPlusTM was used to evaluate the benefit of applying this new foam glass on the reduction on space conditioning loads, especially in relatively colder zones.

Reuse of mineral wool waste and recycled glass in ceramic foams

Abstract Novel ceramic foams have been prepared by high temperature sintering of waste mineral wool and waste glass using SiC as a foaming agent. The aim of the research was to understand the effects of composition and sintering conditions on the properties and microstructure and produce commercially exploitable ceramic foams. Optimum ceramic foams were formed from 40 wt% mineral wool waste and 2 wt% SiC, sintered at 1170 °C using a heating rate of 20 °C/min with a 20 min hold at peak temperature. The ceramic foams produced had a bulk density of 0.71 g/cm3 and a uniform pore size distribution. The research shows that ceramic foams can be formed from waste mineral wool and these can be used for thermal insulation with associated economic and environmental benefits.

Analysis of the mechanical behaviour of the cement mortars with additives of mineral wool fibres from recycling of CDW

Abstract This research analyses the viability of the valuation of mineral wool waste from construction and demolition waste (CDW) as reinforcement of cement matrices. The objective is to analyse the mechanical behaviour of a material composed of a cement mortar matrix to which the aforementioned waste is incorporated. For this purpose, an experimental plan is made in which cement mortar specimens are made with different % of different types of waste, on which Shore D surface hardness, Module of Young, fracture energy, flexural and compressive strength and microscopy tests are carried out, to evaluate their viability as a reinforcement material. The results of the tests show that although the mechanical resistance decreases there is a good connection between the cementitious matrix and the waste resulting in a sustainable alternative to the fibres used today.

Structure, composition and properties of geopolymers from mineral wool waste

Structure, composition and properties of geopolymers from mineral wool waste

Feasibility of the use of mineral wool fibres recovered from CDW for the reinforcement of conglomerates by study of their porosity

Mineral wool is currently the most used insulation in the European Union, and quantities of this waste have increased alarmingly in the last decade, making it essential to recycle or reuse the material, which is not current practice. This study aims to verify the feasibility of compounds of a cement base with additives of insulating mineral fibre residues recovered from the recycling of construction and demolition waste (CDW). For this purpose, experiments were designed to classify the physical–chemical behaviour of architectural mineral wool waste, and that of mortars incorporating them to determine their porosity due to the effects of these fibres on the properties of the compounds. The results obtained show that both the structure and chemical composition as well as the microstructure of the reinforced mortars are viable, and that they would therefore be a sustainable alternative to the current mortars of composite materials.

Pulverization of fibrous mineral wool waste

The total annual volume of mineral wool waste in the 27 European Union countries is expected to increase to 2.5 million tons per year by 2020. Unfortunately, mineral wool wastes are often considered unrecyclable, because their physical characteristics make them difficult to process. In many cases, the problem is caused by the material’s fibrousness. However, no studies have considered comminution methods for mineral wools. The objective of the present study is to investigate how various comminution mechanisms affect mineral wools’ physical characteristics, including appearance, bulk density, and fiber length and width. The study’s results show that compression-based methods (vibratory disc mill and hydraulic press) completely break down mineral wools’ fibrousness, whereas methods based on high cutting speeds affect bulk density and fiber length only moderately. In addition, the present study identifies a rapid method that can be used in a novel way to analyze a large number of mineral wool fibers.

Mechanical and Physical Properties of Soil-Cement Blocks Reinforced with Mineral Wool and Sisal Fiber

AbstractTo address the large house-building demand in developing countries, soil can be used as an alternative building material because of its high availability as a source material, its ease of processing, and its low environmental impact. In this work, soil-cement blocks (SCBs) with three different contents of mineral wool waste and soil-cement blocks with three different contents of sisal fiber were fabricated, microstructurally characterized, and tested after curing for moisture absorption, abrasion resistance, compression, bending, and accelerated erosion. An increase of 29% in compression resistance was found when 1% of mineral wool was loaded into the SCBs, whereas an increase of 0.1% of sisal fiber lead to a 20-fold increase of the rupture modulus (MR). From the results it is observed that both bending strength and compression resistance increased with the addition of mineral wool waste and sisal fiber.

Rockwool waste in fly ash geopolymer composites

Mineral wool waste is often considered unrecyclable, due to its difficult-to-process physical composition, and potential microbial contamination in the post-consumer products. Total mineral wool waste generated in the EU is growing continuously and is currently over 2.3 Mt annually, volumetrically accounting for the largest single waste source in some landfills. Here, we take advantage of the alkali-soluble nature of the rockwool waste, and use a combined mixing and dissolution method to prepare this otherwise unusable waste for geopolymerization, with up to 33 % inclusion in the final product. This mixing and dissolution step enables sufficiently high solids content to form a castable geopolymer paste, which forms a rigid matrix and a compressive strength of 12.8 MPa, sufficient for structural applications. This is the first time mineral wool waste has been used as a geopolymer precursor. FESEM and XRD analysis of the formed products were performed to verify geopolymer formation. Using the preparation reported here, otherwise unrecyclable mineral wool waste can potentially be turned into a valuable raw material for geopolymer materials.

Utilization of Mineral Wools as Alkali-Activated Material Precursor.

Mineral wools are the most common insulation materials in buildings worldwide. However, mineral wool waste is often considered unrecyclable because of its fibrous nature and low density. In this paper, rock wool (RW) and glass wool (GW) were studied as alkali-activated material precursors without any additional co-binders. Both mineral wools were pulverized by a vibratory disc mill in order to remove the fibrous nature of the material. The pulverized mineral wools were then alkali-activated with a sodium aluminate solution. Compressive strengths of up to 30.0 MPa and 48.7 MPa were measured for RW and GW, respectively, with high flexural strengths measured for both (20.1 MPa for RW and 13.2 MPa for GW). The resulting alkali-activated matrix was a composite-type in which partly-dissolved fibers were dispersed. In addition to the amorphous material, sodium aluminate silicate hydroxide hydrate and magnesium aluminum hydroxide carbonate phases were identified in the alkali-activated RW samples. The only crystalline phase in the GW samples was sodium aluminum silicate. The results of this study show that mineral wool is a very promising raw material for alkali activation.

Comparison of the effectiveness of different types of extractants for recovery of iron from mineral wool waste

Comparison of the effectiveness of different types of extractants for recovery of iron from mineral wool waste

Evaluation of the possibility to use organic acids solutions for production of fertilizers based on horticultural mineral wool waste

Evaluation of the possibility to use organic acids solutions for production of fertilizers based on horticultural mineral wool waste

Treating landfill gas hydrogen sulphide with mineral wool waste (MWW) and rod mill waste (RMW)

Hydrogen sulphide (H2S) gas is a major odorant at municipal landfills. The gas can be generated from different waste fractions, for example demolition waste containing gypsum based plaster board. The removal of H2S from landfill gas was investigated by filtering it through mineral wool waste products. The flow of gas varied from 0.3l/min to 3.0l/min. The gas was typical for landfill gas with a mean H2S concentration of ca. 4500ppm. The results show that the sulphide gas can effectively be removed by mineral wool waste products. The ratios of the estimated potential for sulphide precipitation were 19:1 for rod mill waste (RMW) and mineral wool waste (MWW). A filter consisting of a mixture of MWW and RMW, with a vertical perforated gas tube through the center of filter material and with a downward gas flow, removed 98% of the sulfide gas over a period of 80days. A downward gas flow was more efficient in contacting the filter materials. Mineral wool waste products are effective in removing hydrogen sulphide from landfill gas given an adequate contact time and water content in the filter material. Based on the estimated sulphide removal potential of mineral wool and rod mill waste of 14g/kg and 261g/kg, and assuming an average sulphide gas concentration of 4500ppm, the removal capacity in the filter materials has been estimated to last between 11 and 308days. At the studied location the experimental gas flow was 100 times less than the actual gas flow. We believe that the system described here can be upscaled in order to treat this gas flow.

Mineral wool waste in Europe: a review of mineral wool waste quantity, quality, and current recycling methods

The construction and demolition (C&D) industry has been identified as a major source of waste. European Union legislation states that, by 2020, 70 % of C&D waste must be prepared for reuse, recycled or recovered. European Union member states must increase their C&D waste recycling percentages in order to meet this binding target. Utilization of mineral wool waste, often considered unrecyclable, could improve the recycling percentage of C&D waste. In this article, mineral wool production and waste volumes are estimated based on information from the Eurostat database. A literature survey is conducted to collect information about mineral wool material properties, current recycling methods, and barriers to recycling of mineral wool, and suitable methods for separating mineral wool from C&D waste streams and the economic viability of mineral wool recycling are discussed. It is noted that accurate estimation of mineral wool waste volumes is problematic due to the fragmented nature of available data. Based on the literature review, current methods for recycling mineral wool waste include utilization of mineral wool waste as a raw material in various products. Barriers to recycling include economic questions and issues related to the purity and health effects of mineral wool waste. Material properties of mineral wool waste, such as fire resistance, could provide improved properties in products utilizing mineral wool waste as a raw material.

Sukepusios keramikos iš Dysnos radimvietės molio ir liesinančių priedų savybių tyrimai

Perdirbti mineralinės vatos centrifugavimo atliekas yra esminga problema. Darbe pateikti tyrimo rezultatai rodo, kad sukepusi keramika iš lengvai lydaus ilitinio molio ir mineralinės vatos centrifugavimo atliekų yra perspektyvus būdas mineralinės vatos atliekų naudojimo klausimui spręsti. Tiriamosios sistemos savybių tyrimai parodė, kad į lengvai lydųjį molį pridėjus 20 % šių atliekų, gauta sukepusi keramika. Nustatyta, kad išdegus bandinius esant 1040 ºC temperatūrai, tokios keramikos įmirkio vertė yra 2,02 %, tankis – 2169 kg/m3. Dilatometrinių tyrimų rezultatai parodė, kad į Dysnos radimvietės molį pridėjus liesinančio priedo – 20 % mineralinės vatos centrifugavimo atliekų, ilgio pokytis, esant 1070 ºC temperatūrai, sumažėjo nuo 2,8 % iki 1,4 %.